U.S. patent application number 14/371678 was filed with the patent office on 2014-11-13 for x-ray inspection device.
This patent application is currently assigned to YAMAHA HATSUDOKI KABUSHIKI KAISHA. The applicant listed for this patent is Naonobu Ookawa. Invention is credited to Naonobu Ookawa.
Application Number | 20140334605 14/371678 |
Document ID | / |
Family ID | 48781128 |
Filed Date | 2014-11-13 |
United States Patent
Application |
20140334605 |
Kind Code |
A1 |
Ookawa; Naonobu |
November 13, 2014 |
X-RAY INSPECTION DEVICE
Abstract
Provided is an X-ray inspection device having a pair of conveyor
frames that is disposed symmetrically with respect to a center line
as an axis along a substrate conveying direction, and clamps a
printed substrate in a substrate width direction. A substrate
conveying mechanism conveys in an X axis direction the printed
substrate supported by the conveyor frames. A distance adjustment
mechanism drives the pair of conveyor frames so that the conveyor
frames approach or depart from each other in the Y axis direction,
thereby adjusting the width dimension of a printed substrate that
can be conveyed by the substrate conveying mechanism disposed on
each of the conveyor frames.
Inventors: |
Ookawa; Naonobu;
(Shizuoka-ken, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ookawa; Naonobu |
Shizuoka-ken |
|
JP |
|
|
Assignee: |
YAMAHA HATSUDOKI KABUSHIKI
KAISHA
Shizuoka-ken
JP
|
Family ID: |
48781128 |
Appl. No.: |
14/371678 |
Filed: |
June 27, 2012 |
PCT Filed: |
June 27, 2012 |
PCT NO: |
PCT/JP2012/004174 |
371 Date: |
July 10, 2014 |
Current U.S.
Class: |
378/62 |
Current CPC
Class: |
H05K 13/082 20180801;
G01T 7/08 20130101; G01N 23/043 20130101; G01N 2223/6113 20130101;
H05K 2203/163 20130101; H05K 3/341 20130101 |
Class at
Publication: |
378/62 |
International
Class: |
G01N 23/04 20060101
G01N023/04; G01T 7/08 20060101 G01T007/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 12, 2012 |
JP |
2012-004380 |
Claims
1. An X-ray inspection device that is used on a conveyance path for
conveying a printed substrate in a predetermined substrate
conveying direction, comprising: a substrate table configured to
hold the printed substrate; an X-ray source configured to irradiate
X-rays onto the printed substrate held on the substrate table; an
X-ray camera unit facing the X-ray source across the substrate
table, the X-ray camera unit includes an X-ray camera that captures
an X-ray image of the printed substrate held on the substrate
table, the X-ray camera unit enabling the X-ray camera to move
along a plane relative to the X-ray source so as to execute an
oblique view capturing taken by diagonally capturing an essential
inspection area, upon irradiating X-rays at a predetermined
elevation angle onto the substrate; a frame forming a main body of
the substrate table, the frame having an opening to transmit
X-rays; a pair of conveyor frames configured to clamp the printed
substrate with respect to a substrate width direction which is
orthogonal to the substrate conveying direction in a horizontal
plane; a pair of substrate conveyors, each substrate conveyor being
disposed on a respective pair of the conveyor frames, the pair of
substrate conveyors forming a substrate conveying mechanism
configured to convey a printed substrate supported by the pair of
conveyor frames in the substrate conveying direction; a distance
adjustment mechanism configured to drive the pair of conveyor
frames so that each of the pair of conveyor frames approaches or
departs from each other in the substrate width direction, thereby
adjusting a width dimension for allowing a printed substrate to be
conveyed by the substrate conveying mechanism; a movable frame
being disposed on a lower surface of the frame; and a table driving
mechanism including the movable frame, the table driving mechanism
being configured to drive the substrate table via the movable frame
in a horizontal direction that is orthogonal to the substrate
conveying direction, wherein the distance adjustment mechanism is
configured to drive the pair of conveyor frames such that the
conveyor frames equally approach or depart from each other, the
pair of conveyor frames is disposed on the frame symmetrically with
respect to a center axis of the opening along the substrate
conveying direction, and the movable frame has a frame structure of
which a center is open similarly to the frame, and each of the pair
of conveyor frames has a facing edge that the conveyor frame faces
in the substrate width direction, and a bevel, which inclines such
that a downstream side in an X-ray irradiation direction of the
X-ray irradiation unit is wider, and is formed on the facing
edge.
2-3. (canceled)
4. The X-ray inspection device according to claim 1, wherein the
frame has four sides forming the opening of a square in planar
view, and, out of the four sides, at least sides along the
substrate conveying direction have a bevel inclining such that a
downstream side in an X-ray irradiation direction of the X-ray
irradiation unit is wider.
5. (canceled)
6. The X-ray inspection device according to claim 1, wherein the
distance adjustment mechanism includes: double-end studs extending
in the substrate width direction, screw directions of each
double-ends stud at one end and at the other end being set to be
opposite; a first nut mechanism installed in one of the conveyor
frames, the first nut mechanism being screwed into one end of the
double-end studs; a second nut mechanism installed in the other
conveyor frame, the second nut mechanism being screwed into other
end of the double-end studs; a motor configured to drive the
double-end studs; and a power transfer unit configured to transfer
power of the motor to both the double-end studs in a same direction
at a same speed.
7. The X-ray inspection device according to claim 1, wherein the
substrate conveying mechanism further includes a conveyor driving
mechanism configured to drive the pair of substrate conveyors, the
conveyor driving mechanism includes a motor, a drive shaft
rotary-driven by the motor, and a first output pulley and a second
output pulley connected to the drive shaft, and the first output
pulley and the second output pulley are connected with the drive
shaft such that rotation of the first output pulley and the second
output pulley is restricted and the first output pulley and the
second output pulley are movable with respect to an axis direction
of the drive shaft, the first output pulley transferring power to
one of the substrate conveyors and the second output pulley
transferring power to the other substrate conveyor.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of priority to Japanese
Patent Application 2012-004380 filed on Jan. 12, 2012, and to
International Patent Application No. PCT/JP2012/004174 filed on
Jun. 27, 2012, the entire content of each of which is incorporated
herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to an X-ray inspection
device.
BACKGROUND
[0003] To inspect a printed substrate on which many electronic
components are mounted, an X-ray inspection device using X-rays is
known, as disclosed in Japanese Patent Application Laid-open No.
2003-315288 and Japanese Patent Application Laid-open No.
2002-189002. In such an X-ray inspection device, an inspection
chamber is defined in a housing at which X-ray shielding processing
has been performed to prevent exposure to X-rays, an X-ray source
and an X-ray camera are installed in the inspection chamber, and
X-rays are irradiated onto an inspection target (a printed
substrate) and an X-ray image is captured using these devices. In
order to carry a printed substrate into/out of the inspection
chamber, a substrate table, to transfer the printed substrate on
the substrate conveyor, is disposed in the housing.
[0004] Referring to FIG. 15, conveyor units 70P are disposed on a
substrate table 60P, as disclosed in Japanese Patent Application
Laid-open No. 2003-315288. The conveyor units 70P clamp a printed
substrate W therebetween with respect to a substrate width
direction (hereafter called "Y axis direction") which is orthogonal
to the carry in/out direction of the printed substrate W (hereafter
called "X axis direction"). Since a dimension in the Y axis
direction of the target printed substrate W for inspection varies
respectively, a width adjustment unit for adjusting the space
between the conveyor units 70P is disposed on the substrate table
60P of Japanese Patent Application Laid-open No. 2003-315288. The
width adjustment unit is configured by a fixed frame 71P which
secures the conveyor units 70P to a base 61P of the substrate table
60P, and a movable frame 72P which is movable in the Y axis
direction from the fixed frame 71P. When clamping a printed
substrate W between the fixed frame 71P and the movable frame 72P,
the movable frame 72P moves in the Y axis direction so as to adjust
the dimension in the Y axis direction.
[0005] As the high integration of printed substrates are promoted
in recent years, the use of transmission imaging where X-rays
diagonally irradiated onto an essential inspection area at an
elevation angle with respect to a plane of the printed substrate
(called "oblique view capturing" in the present description), in
addition to transmission imaging where X-rays, are irradiated in a
normal line direction of the printed circuit (called "direct view
imaging" in the present description), is increasingly demanded when
X-ray transmission inspection is performed on a printed
substrate.
[0006] In the case of a configuration of Japanese Patent
Application Laid-open No. 2003-315288, where a plurality of types
of printed substrates W are clamped using the fixed frame 71P and
the movable frame 72P, the space for an opening required for
transmitting X-rays increases if X-ray inspection is executed using
both the oblique view capturing and the direct view imaging, which
could increase the size of the entire apparatus.
[0007] FIGS. 16A-16D are comparative diagrams depicting a
cross-sectional view of an X-ray inspection device in which an
X-ray source (not illustrated) is disposed above, and an X-ray
camera is movably disposed below. FIG. 16A and FIG. 16B are
diagrams according to the present invention, and FIG. 16C and FIG.
16D are diagrams according to the prior art. FIG. 16C and FIG. 16D
show a state when a substrate table 60P of Japanese Patent
Application Laid-open No. 2003-315288 shown in FIG. 15, for
example, is used, and the substrate table 60P is supported on a
frame 111P having an opening 120 to transmit X-rays between the
X-ray source and the X-ray camera 50.
[0008] In order to perform the oblique view capturing using the
fixed frame 71P in FIG. 16C and FIG. 16D, a space d2, to transmit
X-rays, must be secured in advance as indicated by d2 in FIG. 16C,
hence the fixed frame 71P is disposed at a position where the
opening of the base 61P is always blocked. Therefore if the oblique
view capturing is not required, the fixed frame 71P gets in the way
and limits the width of a printed substrate W, which is required
for direct view imaging.
SUMMARY
[0009] With the foregoing in view, it is an object of the present
invention to provide an X-ray inspection device that can eliminate
unnecessary limitations when the oblique view capturing is used
with the direct view imaging.
[0010] To solve this problem, the present invention provides an
X-ray inspection device that is used on a conveyance path for
conveying a printed substrate in a predetermined substrate
conveying direction, having: a pair of conveyor frames configured
to clamp the printed substrate with respect to a substrate width
direction which is orthogonal to the substrate conveying direction
in a horizontal plane; a pair of substrate conveyors, each
substrate conveyor being disposed on the respective pair of the
conveyor frames, the pair of substrate conveyors forming a
substrate conveying mechanism configured to convey a printed
substrate supported by the pair of conveyor frames in the substrate
conveying direction; and a distance adjustment mechanism configured
to drive the pair of conveyor frames so that each of the pairs of
conveyor frames approaches or departs from each other in the
substrate width direction, thereby adjusting a width dimension for
allowing a printed substrate to be conveyed by the substrate
conveying mechanism. In this aspect, a printed substrate clamped by
a pair of conveyor frames is supported by the conveyor frames. The
printed substrate supported by each conveyor frame is carried into
the conveyor frame or carried out of the conveyor frame by a
substrate conveying mechanism. The substrate conveying mechanism is
formed by a pair of substrate conveyors disposed in the pair of
conveyor frames respectively. Therefore the substrate conveying
mechanism can adjust the width of a printed substrate that the
substrate conveying mechanism is capable of carrying, by changing
the space between the conveyor frames. Since the distance
adjustment mechanism can adjust the space between the conveyor
frames in the substrate width direction, various kinds of printed
substrates can be supported within a range where the pair of
conveyor frames can move. Here the distance adjustment mechanism
drives the pair of conveyor frames so that each of the pair of
conveyor frames approaches or departs from each other in the
substrate width direction. This means that when a printed substrate
which requires only the direct view imaging is held, even a printed
substrate whose width dimension extends over the entire width of
the opening can receive X-ray inspection. Moreover, the space is
adjusted by moving the pair of conveyor frames respectively, hence
the driving time can be reduced compared with a case when one of
the conveyor frames is fixed and the other conveyor frame is
movable.
[0011] In the X-ray inspection device, it is preferable that the
distance adjustment mechanism drives the pair of conveyor frames
such that the conveyor frames equally approach or depart from each
other. In this aspect, the driving amount by each conveyor frame is
equal, so the driving time can be decreased. Further, the center
line that bisects the width of the printed substrate can be matched
with the center position of the pair of conveyor frames in an
approaching/departing direction. Hence in the case when an opening
to transmit X-rays is disposed, centering with this opening is
easier.
[0012] Preferably another mode further includes a frame having an
opening to transmit X-rays, wherein the pair of conveyor frames is
disposed on the frame symmetrically with respect to a center axis
of the opening along the substrate conveying direction. In this
aspect, the conveyor frames are disposed symmetrically with respect
to the opening of the frame, and the distance adjustment mechanism
drives each of the conveyor frames such that the conveyor frames
equally approach or depart from each other along the substrate
width direction, therefore each conveyor frame equally opens the
opening in the printed substrate width direction while maintaining
symmetry with respect to the center line of the opening along the
substrate conveying direction. This means that the center line,
that bisects the printed substrate width direction, can be matched
with the center line of the opening, and therefore when the oblique
view capturing is executed for a printed substrate held on the
substrate table, the frame to support the substrate table can
remain compact. Furthermore, a configuration to symmetrically move
the pair of conveyor frames with respect to the frame is used.
Hence the opening of the frame can be opened over the entire width.
This means that when a printed substrate which requires only the
direct view imaging is held, even a printed substrate whose width
dimension extends over the entire width of the opening can receive
X-ray inspection.
[0013] In the X-ray inspection device, it is preferable that the
frame has four sides forming the opening of a square in planar
view, and, out of the four sides, at least sides along the
substrate conveying direction have a bevel inclining such that a
downstream side in an X-ray irradiation direction of the X-ray
irradiation unit is wider. In this aspect, the path of X-rays can
be opened using the bevels when the oblique view capturing is
performed, whereby the oblique view capturing becomes possible for
a wider printed substrate.
[0014] In the X-ray inspection device, it is preferable that each
of the pair of conveyor frames has a facing edge facing to each
other with respect to the substrate width direction, and a bevel is
formed on the facing edge, the bevel inclining such that a
downstream side in an X-ray irradiation direction of the X-ray
irradiation unit is wider. In this aspect, a wider effective
opening diameter to transmit X-rays can be secured by the bevels,
whereby the oblique view capturing becomes possible for an even
wider printed substrate.
[0015] In the X-ray inspection device, it is preferable that the
distance adjustment mechanism includes: double-end studs extending
in the substrate width direction, screw directions of each
double-ends stud at one end and at the other end being set to be
opposite; a first nut mechanism installed in one of the conveyor
frames, the first nut mechanism being screwed into one end of the
double-end studs; a second nut mechanism installed in the other
conveyor frame, the second nut mechanism being screwed into other
end of the double-end studs; a motor configured to drive the
double-end studs; and a power transfer unit configured to transfer
power of the motor to both the double-end studs in a same direction
at a same speed. In this aspect, if the double-end stud rotates in
one direction (e.g. clockwise), the nut mechanisms screwed into the
double-end studs transfer a force to the corresponding conveyor
frames in directions for the conveyor frames to approach or depart
from each other, and if the double-end studs rotate in the other
direction (e.g. counterclockwise), the nut mechanisms screwed into
the double-end studs transfer a force to the corresponding conveyor
frames in directions to move the conveyor frames in the opposite
directions from above. Therefore the pair of conveyor frames can be
simultaneously driven using the single motor, whereby the drive
system can be simplified and the number of components can be
decreased.
[0016] In the X-ray inspection device, it is preferable that the
substrate conveying mechanism further includes a conveyor driving
mechanism configured to drive the pair of substrate conveyors, the
conveyor driving mechanism includes a motor, a drive shaft being
rotary-driven by the motor, and a first output pulley and a second
output pulley being connected to the drive shaft, and the first
output pulley and the second output pulley are connected with the
drive shaft such that rotation of the first output pulley and the
second output pulley are restricted but are movable with respect to
an axis direction of the drive shaft, the first output pulley
transferring power to one of the substrate conveyors and the second
output pulley transferring power to the other substrate conveyor.
In this aspect, the drive shaft is rotated by the rotation of the
motor. The torque thereof is transferred to the substrate conveyors
via the first and second output pulleys respectively. Therefore the
substrate conveyors are simultaneously driven by the single motor
in a same direction. The first output pulley and the second output
pulley form a pair, so as to be movable in the axis direction of
the drive shaft, in a state where rotation around the axis of the
drive shaft is restricted respectively. Hence power can be
transferred to each of the substrate conveyors without interrupting
the displacement of the conveyor frames by the distance adjustment
mechanism.
[0017] As described above, the present invention uses a
configuration to move the pair of conveyor frames in the substrate
width direction. Hence the opening of the frame can be opened over
the entire width. This means that when a printed substrate which
requires only the direct view imaging is held, even a printed
substrate whose width dimension extends over the entire width of
the opening can receive X-ray inspection. Therefore unnecessary
restrictions can be eliminated when both the oblique view capturing
and the direct view imaging are used, which is a remarkable effect.
Furthermore, space is adjusted by moving the pair of conveyor
frames respectively. Hence the present invention is advantageous in
that the driving time can be reduced compared with the case when
one of the conveyor frames is fixed and the other conveyor frame is
movable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a perspective view depicting an appearance of an
X-ray inspection device according to an embodiment of the present
invention.
[0019] FIG. 2 is a perspective view depicting a structure of the
X-ray inspection device in FIG. 1.
[0020] FIG. 3 is a perspective view depicting a general
configuration of an X-ray camera unit that is used for the X-ray
inspection device in FIG. 1.
[0021] FIG. 4 is a perspective view depicting a general
configuration of a substrate table used for the X-ray inspection
device in FIG. 1.
[0022] FIG. 5 is an enlarged perspective view of the substrate
table in FIG. 4.
[0023] FIG. 6 is a plan view of the substrate table in FIG. 4.
[0024] FIG. 7 is a perspective view depicting a clamp mechanism of
the substrate table in FIG. 4.
[0025] FIG. 8 is an enlarged partial cross-sectional view depicting
an essential area of the substrate table in FIG. 4.
[0026] FIG. 9 is an enlarged partial cross-sectional view depicting
an essential area of the substrate table in FIG. 4.
[0027] FIG. 10 is a cross-sectional view depicting a downstream
side of the X-ray inspection device in FIG. 1 in the substrate
conveying direction.
[0028] FIG. 11 is a cross-sectional view depicting the back surface
side of the X-ray inspection device in FIG. 1.
[0029] FIG. 12 is a cross-sectional view depicting the back surface
side of the X-ray inspection device in FIG. 1.
[0030] FIG. 13 is a block diagram depicting a control unit of the
X-ray inspection device in FIG. 1.
[0031] FIG. 14 is a flow chart depicting an inspection operation by
the X-ray inspection device in FIG. 1.
[0032] FIG. 15 is a prior art schematic cross-sectional view
depicting a general configuration of a substrate table of a prior
art.
[0033] Fis. 16A to 16D are comparison diagrams depicting functional
effects of the present invention, where FIG. 16A is a schematic
cross-sectional view depicting a case of inspecting a small width
printed substrate according to the present embodiment, FIG. 16B is
a schematic cross-sectional view depicting a case of inspecting a
large width printed substrate according to the present embodiment,
FIG. 16C is a prior art schematic cross-sectional view depicting a
case of inspecting a small width printed substrate when the prior
art in FIG. 15 is used, and FIG. 16D is a prior art schematic
cross-sectional view depicting a case of inspecting a large width
printed substrate when the prior art in FIG. 15 is used.
[0034] FIG. 17A is a diagram depicting a change of magnification of
an X-ray image in a close up position by the X-ray camera unit that
is used for a composite inspection device in FIG. 1.
[0035] FIG. 17B is a diagram depicting a change of magnification of
an X-ray image in a non-close up position by the X-ray camera unit
that is used for the composite inspection device in FIG. 1.
DETAILED DESCRIPTION
[0036] Preferred embodiments of the present invention will now be
described with reference to the accompanying drawings. In the
following description, each component of an X-ray inspection device
10 according to an embodiment of the present invention will be
described based on a rectangular coordinate system, where the
X-axis is a direction in which a target printed substrate W for
inspection is conveyed, the Y axis is a substrate width direction
which is orthogonal to the X axis in a horizontal plane, and the Z
axis is the vertical direction. On the printed substrate W, many
electronic components are mounted and electric conduction portions
are soldered. The X-ray inspection device 10 according to this
embodiment is configured to inspect for the acceptance of a printed
substrate W mainly by inspecting each soldered portion of the
electronic components.
[0037] As illustrated in FIG. 1, the X-ray inspection device 10 is
disposed between a substrate conveyor 12 that carries a board W in
after the upstream process is completed, and a substrate conveyor
14 that carries the board W out after the X-ray inspection is
completed. The substrate conveyor 12 is formed by a pair of belt
conveyors 12a and 12b, and the substrate conveyor 14 is formed by a
pair of belt conveyors 14a and 14b. Depending on the specification
of the facility where the X-ray inspection device 10 is installed,
one of the substrate conveyors 12 and 14 becomes a board carry-in
conveyor and the other becomes a board carry-out conveyor. In this
example in FIG. 1, it is assumed that the substrate conveyor 12 on
the right side is the carry in side, and the substrate conveyor 14
on the left side is the carry-out side.
[0038] The X-ray inspection device 10 has a housing 11 shielded by
lead or the like. The housing 11 has an approximate cube shape. A
front surface 11a of the housing 11 faces one side of the Y axis
direction. In a facility where the X-ray inspection device 10 is
installed, a printed substrate W carried in from the board carry-in
conveyor (substrate conveyor 12) is inspected inside the housing
11, and is then carried out from the X-ray inspection device 10 to
the board carry-out conveyor (substrate conveyor 14). On the walls
11b and 11c of the housing 11, which the substrate conveyors 12 and
14 face, a shutter mechanism (not illustrated) is disposed
respectively, and a printed substrate W is carried in and out
through the board carry in/out ports 11d and 11e (see FIG. 2),
which are opened or closed by the pair of shutter mechanisms.
[0039] As illustrated in FIG. 2, a structure 20 to support each
device installed in the X-ray inspection device 10 is constructed
inside the housing 11. The structure 20 includes a base 21 which
constitutes a bottom portion of the housing 11, a pair of gate
portions 22 and 23 which are erected on the base 21, each gate
portion respectively reinforces the inner wall portions in the X
axis direction, a pair of frame portions 24 and 25 which are
respectively fixed to the center portions of the gate portions 22
and 23, and a beam 30 which bridges between the pair of frame
portions 24 and 25. Each component of the structure 20 is formed by
combining various steel materials and sheet metal members.
[0040] A bottom portion 21a is formed on the base 21 such that the
center portion with respect to the X axis direction, denting in a
rectangular shape, extends along the Y axis direction. A later
mentioned X-ray camera unit 40 (see FIG. 3) is installed on the
bottom portion 21a. On each side of the bottom portion 21a of the
base 21, a shelf portion 21b, which partially protrudes toward the
center side in the X axis direction and extends horizontally in the
Y axis direction, is integrally provided respectively. On the upper
surface of each shelf portion 21b, a Y axis rail 26 (27) that faces
the gate portion 22 (23) is disposed respectively. Each Y axis rail
26 (27) constitutes an essential area of a later mentioned table
driving mechanism 100. The table driving mechanism 100 includes a
movable frame 111. A later mentioned substrate table 60 is placed
on the Y axis rails 26 and 27 via the movable frame 111, so as to
be movable back and forth along the Y axis rails 26 and 27.
[0041] Each gate portion 22 (23) is formed in a gate shape which
extends over the corresponding board carry in/out port 11d (11e) of
the housing 11, and includes a shutter mechanism (not illustrated)
disposed on the corresponding wall 11b (11c) of the housing 11
respectively.
[0042] The lower part of each frame portion 24 (25) is welded to
the upper part of the corresponding gate portion 22 (23), and the
upper surface thereof is welded to each edge of the beam 30 in the
X axis direction. The frame portions 24 and 25, together with the
gate portions 22, 23 and the beam 30, construct a firm frame
structure.
[0043] The beam 30 is a structure to support an X-ray irradiation
unit 160 as an X-ray source, which is described in detail later
(see FIG. 10 to FIG. 12).
[0044] As illustrated in FIG. 3, the X-ray camera unit 40 includes:
a pair of X axis guide rails 41 and 42 which are disposed in the
bottom portion 21a of the base 21, and extend in the X axis
direction with a space therebetween in the Y axis direction
therebetween; an X axis slide table 43 which is guided on the X
axis guide rails 41 and 42 so as to move in the X axis direction;
an X axis ball screw mechanism 44 which is disposed in the lower
part of the X axis slide table 43 and drives the X axis slide table
43 in the X axis direction; a pair of Y axis guide rails 45 and 46
which are fixed to the upper part of the X axis slide table 43 and
extend in the Y axis direction respectively; a Y axis slide table
47 which is guided by the Y axis guide rails 45 and 46 so as to
move in the Y axis direction; a Y axis ball screw mechanism 48
which is disposed in the lower part of the Y axis slide table 47
and drives the Y axis slide table 47 in the Y axis direction; and
an X-ray camera 50 which is installed on the Y axis slide table
47.
[0045] The X axis guide rails 41 and 42 are disposed slightly to
the rear in the center area of the bottom portion 21a, and guide
the X axis slide table 43 in this position to reciprocate in the X
axis direction.
[0046] The X axis slide table 43 is formed in a rectangle extending
in the Y axis direction in plane view.
[0047] The X axis ball screw mechanism 44 includes: an X axis motor
44a installed in the bottom portion 21a; a ball screw 44b which is
rotary-driven by the X axis motor 44a; and a nut unit 44c which is
screwed into the ball screw 44b and is fixed to the bottom surface
of the X axis slide table 43, so that the X axis slide table 43 can
reciprocate in the X axis direction by the nut unit 44c, which
moves in the X axis direction by the rotation of the ball screw
44b.
[0048] The Y axis guide rails 45 and 46 are disposed with a space
therebetween in the width direction (X axis direction) of the X
axis slide table 43. The Y axis guide rails 45 and 46 extend over
approximately the entire length of the X axis slide table 43 in the
Y axis direction. The Y axis guide rails 45 and 46 guide the Y axis
slide table 47 so that the Y axis slide table 47 reciprocates in
the Y axis direction.
[0049] The Y axis slide table 47 is a rectangular member which is
slightly longer in the X axis direction in planar view. The Y axis
slide table 47 supports the X-ray camera 50 on the upper surface
thereof. This means that the X-ray camera 50 can move freely in the
longitudinal and lateral directions (XY axis directions) on the
bottom portion 21a by the movement of the X axis slide table 43 and
the Y axis slide table 47. Since the X-ray camera 50 is placed on
the Y axis slide table 47, the X-ray camera 50 slightly projects
upward from the shelf portion 21b of the base 21.
[0050] The Y axis ball screw mechanism 48 includes a Y axis motor
48a installed in a rear end of the X axis slide table 43; a ball
screw 48b which is rotary-driven by the Y axis motor 48a; and a nut
unit 48c which is screwed into the ball screw 48b and is fixed to
the bottom surface of the Y axis slide table 47, so that the Y axis
slide table 47 can reciprocate in the Y axis direction by the nut
unit 48c, which moves in the Y axis direction by the rotation of
the ball screw 48b.
[0051] As illustrated in FIG. 4 to FIG. 9, a substrate table 60
includes: a frame 61 which is a main body; a conveyor unit 70 that
conveys and supports a printed substrate W on the frame 61; a
conveyor driving mechanism 80 that drives substrate conveyors 73
and 74 disposed on the conveyor unit 70; and a distance adjustment
mechanism 90 that changes an opposing distance of the conveyor unit
70. In the X-ray inspection device 10 according to this embodiment,
a table driving mechanism 100 is also installed in order to drive
the substrate table 60 in the X axis direction and the Y axis
direction (see FIG. 4, FIG. 10 and FIG. 11).
[0052] The frame 61 is connected with the table driving mechanism
100 so as to be movable in the XY axis directions, as described
later. As illustrated, the frame 61 is a square frame integrating a
pair of X axis pieces 62 and 63 which extend in the X axis
direction, and a pair of Y axis pieces 64 and 65 which are disposed
on both ends of the X axis pieces 62 and 63, and extend in the Y
axis direction, and an opening 66, to transmit X-rays RL, is formed
in a square shape in planar view in the center area of the frame 61
(see FIG. 6). The opening 66 has a square shape in planar view
enclosed by sides 62a and 63a along the X axis direction (substrate
conveying direction) and sides 64a and 65a along the Y axis
direction (substrate width direction) such that X-rays transmit
through the opening 66.
[0053] In this embodiment, as illustrated in FIG. 8 and FIG. 9, a
bevel 62b (63b) is formed in the lower edge of each X axis piece 62
(63) that constitutes the opening 66. The bevel 62b (63b) is formed
by chamfering a part of the side 62a (63a) of the opening 66 so
that the lower side of the opening 66 becomes wider. By this bevel
62b, an effective opening width of X-rays RL, that transmits at a
predetermined elevation angle .theta. (angle at which X-rays cross
with printed substrate W: 45.degree. in the example in FIG. 8) is
increased when the oblique view capturing is performed.
[0054] As illustrated in FIG. 5 and FIG. 6, the Y axis rail 67 (68)
is fixed to the upper surface of each Y axis piece 64 (65) of the
frame 61 respectively. A conveyor unit 70 is mounted on the pair of
Y axis rails 67 and 68, and the conveyor unit 70 is constructed to
be movable in the Y axis direction on the Y axis rails 67 and 68.
In this embodiment, the Y axis rails constitute a part of the
distance adjustment mechanism 90 which is described later, and
movably connect a pair of conveyor frames 71 and 72 of the conveyor
unit 70 to the frame 61 in the Y axis direction respectively.
[0055] The conveyor unit 70 includes the pair of conveyor frames 71
and 72 which are disposed on the front and back in the Y axis
direction, and a pair of substrate conveyors 73 and 74 disposed on
the conveyor frames 71 and 72 respectively.
[0056] The conveyor frames 71 and 72 are disposed approximately
symmetrically with respect to a center line 120a in the X axis
direction that passes through the center of the opening 66 (see
FIG. 16A and FIG. 16B), and can clamp a printed substrate W
therebetween by moving toward each other in the Y axis direction
(see FIG. 6).
[0057] As illustrated in FIG. 5 and FIG. 8, each conveyor frame 71
(72) includes: an X axis frame 71a (72a) which extends in the X
axis direction and of which edge projects from the frame 61; a
pressing plate 71b (72b) which is fixed to the upper surface of the
X axis frame 71a (72a) and of which side portion projects to the
opening 66 side; a movable member 71c (72c) which clamps a printed
substrate W in tandem with the pressing plate 71b (72b); a pair of
air cylinders 71d (72d) disposed on both ends of the movable member
71c (72c); a slide member 71e (72e) which is disposed on each air
cylinder 71c (72d) and is connected to the cylinder main unit of
the air cylinder 71d (72d); and a guide rail 71f (72f) which
connects the slide member 71e (72e) to the corresponding X axis
frame 71a (72a) so as to be vertically movable.
[0058] The X axis frame 71a (72a) is a metal member having a square
bar shape, and constitutes a main structure of the conveyor frame
71 (72).
[0059] One end of the pressing plate 71b (72b) in the width
direction (Y axis direction) is fixed to the upper surface of the X
axis frame 71a (72a), and the other end thereof in the width
direction (Y axis direction) projects toward the center of the
frame 61. The total length (length in the X axis direction) of the
pressing plate 71b (72b) is set to be slightly shorter than the
total length (length in the X axis direction) of the X axis frame
71a (72a), and the center of the pressing plate 71b (72b) is
aligned to the center of the X axis frame 71a (72a).
[0060] Each movable member 71c (72c) is disposed under the pressing
plate 71b (72b) so as to contact the inner surface side of the
corresponding X axis frame 71a (72a). A printed substrate W is
conveyed in a state where each end portion of the printed substrate
W in the width direction is caught between the movable member 71c
(72c) and the pressing plate 71b (72b) respectively, and each end
portion of the conveyed printed substrate W in the width direction
is clamped/unclamped with the pressing plate 71b (72b) by a
vertical motion of the movable member 71c (72c). As illustrated in
FIG. 8 and FIG. 9, each movable member 71c (72c) has a facing edge
that the movable member 71c (72c) faces in the Y axis direction. On
each facing edge, a bevel 71i (72i), which inclines such that a
downstream side (lower side in the illustrated example) is wider in
the X-ray irradiation direction of the X-ray irradiation unit 160,
is formed. These bevels 71i and 72i increase the effective opening
diameter when the X-rays transmit through the opening 66.
[0061] Each air cylinder 71d (72d) is fixed to each X axis frame
71a (72a) such that a rod thereof projects upward. Each rod of the
air cylinder 71d (72d) is connected to the movable member 71c (72c)
respectively via a connecting member 71g (72g). Therefore if each
air cylinder 71d (72d) is activated, the air cylinder 71d (72d) can
vertically move the movable member 71c (72c) via the connecting
member 71g (72g).
[0062] Each slide member 71e (72e) is integrated with the rod of
the air cylinder 71d (72d), and is guided by the guide rail 71f
(72f), whereby the movable member 71c (72c) is supported via the
air cylinder 71d (72d) so as to freely move vertically.
[0063] Each guide rail 71f (72f) is disposed outside the air
cylinder 71d (72d) in the X axis direction, and is fixed to the
inner surface side of the X axis frame 71a (72a).
[0064] The pressing plates 71b and 72b, the movable members 71c and
72c, the air cylinders 71d and 72d and the like, which were
described above, constitute a clamp mechanism to clamp a printed
substrate W in the illustrated embodiment.
[0065] Furthermore, in the illustrated embodiment, an air cylinder
75 and a pressing member 76, which constitute a side clamp, are
disposed on one of the conveyor frames (conveyor frame 72 disposed
on the rear side in the Y axis direction in the illustrated
example), in order to position and secure a printed substrate W to
be clamped.
[0066] As illustrated in FIG. 7, the air cylinder 75 is
integratedly installed on the X axis frame 72a at the rear side of
the conveyor frame 72 by a stay (not illustrated). The pressing
member 76 is fitted into a notch formed in the center portion of
the X axis frame 72a in the X axis direction, so as to reciprocate
in the Y axis direction, and can be driven in the Y axis direction
by the air cylinder 75. As illustrated in FIG. 9, the pressing
member 76 is a thin plate member facing the side portion of a
printed substrate W conveyed to an area between the pressing plate
72b and the movable member 72c in the Y axis direction. If the air
cylinder 75 is activated and moves the rod forward in FIG. 9, the
printed substrate W is pressed forward toward the conveyor frame 71
side, whereby the side portion of the printed substrate W is set
along the conveyor frame 71, and can be secured in the width
direction in a state where displacement has been corrected.
Therefore if the printed substrate W is pressed in the width
direction with a predetermined load, and the air cylinders 71d and
72d are activated in this state and the printed substrate W is
clamped between the pressing plates 71b and 72b and the movable
members 71c and 72c, then the printed substrate W can be secured
and accurately positioned in a state where horizontal displacement
has been corrected.
[0067] Each substrate conveyor 73 (74) is a unit which is installed
on a main portion of the air cylinder 71d (72d) and the facing
surface of the slide member 71e (72e), and forms the substrate
conveying mechanism, along with the conveyor driving mechanism 80.
Each substrate conveyor 73 (74) is formed by many rollers 74a
disposed along the surface of each conveyor frame 71 (72) which
face each other, and a belt 74b wound around each roller 74a. The
belt 74b is directly under the pressing plate 71b (72b) in planar
view, and contacts the end portion of the printed substrate W in
the width direction, which is conveyed between the pressing plates
71b and 72b and the movable members 71c and 72c, so as to convey
the printed substrate W. In FIG. 5, the roller and the belt of the
substrate conveyor 73 on the front side are not visible, but have
the same specifications as the roller 74a and the belt 74b of the
substrate conveyor 74 on the rear side.
[0068] As illustrated in FIG. 5, the conveyor driving mechanism 80
is a unit that constitutes, along with the substrate conveyors 73
and 74, the substrate conveying mechanism. The conveyor driving
mechanism 80 includes: a motor 81 which is installed on one end of
the frame 61 in the X axis direction, on the front side in the Y
axis direction, and outputs power in a direction around the Y axis;
a drive shaft 82 which is disposed between the pair of substrate
conveyors 73 and 74 along the Y axis direction, and is
rotary-driven around the Y axis by the motor 81; and output pulleys
83 and 84 which are connected to the front side and the rear side
of the drive shaft 82 in the Y axis direction (see FIG. 6). The
output pulley 83, which is connected to the front side of the drive
shaft 82 in the Y axis direction, outputs power to the belt of the
substrate conveyor 73. The output pulley 84, which is connected to
the rear side of the drive shaft 82 in the Y axis direction,
outputs power to the belt 74b of the substrate conveyor 74. The
drive shaft 82 driven by the motor 81 is formed to have a polygonal
cross-section, and the output pulleys 83 and 84 form a pair, which
is connected to the drive shaft 82 so as to be relatively movable
along the axis direction of the drive shaft 82 (that is, the Y axis
direction), in a state where relative rotation with the drive shaft
82 is restricted. One output pulley 83 (on the front side of the Y
axis direction) constitutes a first output pulley which transfers
power to one substrate conveyor 73 (on the front side in the Y axis
direction). The other output pulley 84 (on the rear side in the Y
axis direction) constitutes a second output pulley which transfers
power to the other substrate conveyor 74 (on the rear side in the Y
axis direction). In the illustrated example, the drive shaft 82 is
supported by a bearing 85 installed on the Y axis piece 65 of the
frame 61, so that the drive shaft 82 can smoothly rotate.
[0069] The distance adjustment mechanism 90 includes: a pair of Y
axis rails 67 and 68; a pair of double-end studs 91 and 92 which
are disposed on both sides of the conveyor frames 71 and 72 in the
X axis direction and extend in the Y axis direction respectively; a
power transfer unit 93 which is disposed on the back surface of the
rear side conveyor frame 72 and transfers a rotary force in a same
direction to the double-end studs 91 and 92; and a motor 94 which
is installed on the other end in the X axis direction (upstream
side in the substrate conveying direction) of the rear side
conveyor frame 72 and outputs rotary force around the Y axis to the
power transfer unit 93. In each double-end stud 91 (92), a right
screw and a left screw are symmetrically formed with respect to the
center in the Y axis direction, and each screw is screwed into a
nut mechanism 95 (96) disposed on the conveyor frame 71 (72)
respectively. The pair of nut mechanisms 95 installed on one X axis
piece 62 (on the front side in the Y axis direction) constitutes a
first nut mechanism, which screws into one end (on the front side
in the Y axis direction) of the corresponding double-end stud 91
(92) respectively. The pair of nut mechanisms 96 installed on the
other conveyor frame 71 (72) (on the rear side in the Y axis
direction) constitutes a second nut mechanism, which screws into
the other end (on the rear side in the Y axis direction) of the
corresponding double-end stud 91 (92) respectively. The output of
the motor 94 is transferred to the pair of double-end studs 91 and
92 by the power transfer unit 93, whereby the pair of double-end
studs 91 and 92 rotate in a same direction at a same speed. If
double-end studs 91 and 92 rotate in one direction (e.g.
clockwise), the double-end studs 91 and 92, in tandem with the nut
mechanisms 95 and 96, move the conveyor frames 71 and 72 to
approach each other, as shown by the virtual line in FIG. 6. If the
double-end studs 91 and 92 rotate in the other direction (e.g.
counterclockwise), the double-end studs 91 and 92 move the conveyor
frames 71 and 72 to depart from each other, as shown by the solid
line in FIG. 6. In this embodiment, by using this mechanism, the
conveyor frames 71 and 72 are driven so as to equally approach or
depart from each other in the Y axis direction, thereby adjusting a
width dimension of the printed substrate W that can be conveyed by
the substrate conveyors 73 and 74 as the substrate conveying
mechanism disposed on each of the conveyor frames 71 and 72.
[0070] As illustrated in FIG. 4 to FIG. 10, the table driving
mechanism 100 includes: an X axis drive unit 110 which drives the
substrate table 60 in the X axis direction; and a Y axis drive unit
140 which drives the substrate table 60 in the Y axis direction via
the X axis drive unit 110 (see FIG. 4).
[0071] The X axis drive unit 110 includes: a movable frame 111
which is disposed on the lower surface of the frame 61 of the
substrate table 60; a pair of X axis rails 112 and 113 which are
disposed on the movable frame 111 with a space therebetween in the
Y axis direction and guide the substrate table 60 in the X axis
direction; and an X axis ball screw mechanism 114 which is disposed
behind the X axis rail 113 on the rear side. The movable frame 111
is a frame-shaped structure of which center is open, as with the
frame 61. The X axis ball screw mechanism 114 includes: a ball
screw 114a which extends in the X axis direction, a nut portion
(not illustrated) which is screwed into the ball screw 114a; and an
X axis motor 114b which drives the ball screw 114a around the X
axis. The nut portion is fixed to the frame 61 of the substrate
table 60. The nut portion receives a rotational force of the ball
screw 114a and transfers the force, to relatively move the
substrate table 60 in the X direction, to the movable frame 111.
This means that if the X axis motor 114b rotates and the ball screw
114a rotates, the substrate table 60 can reciprocate in the X axis
direction by the force in the X axis direction received from the
nut portion.
[0072] As illustrated in FIG. 4, the Y axis drive unit 140
includes: the pair of Y axis rails 26 and 27 disposed on the shelf
portion 21b; and the Y axis ball screw mechanism 141 which is
disposed inside the Y axis rail 26 on the downstream side in the
substrate conveying direction, that is, the X axis direction (the
side where the Y axis rail 26 on the downstream side of the
substrate conveying direction faces the Y axis rail 27 on the
upstream side of the substrate conveying direction in the X axis
direction). The Y axis rails 26 and 27 guide the movable frame 111
respectively so as to reciprocate in the Y axis direction. The Y
axis ball screw mechanism 141 includes: a ball screw 141a that
extends in the Y axis direction; a nut portion (not illustrated)
which screws into the ball screw 141a; and a Y axis motor 141b
which rotary-drives the ball screw 141a. The ball screw 141a is
rotatably supported on the shelf portion 21b by a bearing (not
illustrated). The nut portion is fixed to the lower surface of the
movable frame 111, receives a rotational force of the ball screw
141a, and transfers the force to drive the substrate table 60 in
the Y axis direction via the movable frame 111. This means that if
the Y axis motor 141b rotates and the ball screw 141a rotates, the
substrate table 60 can reciprocate in the Y axis direction by the
force in the Y axis direction received from the nut portion.
[0073] Now an X-ray irradiation unit (an example of an X-ray
source) 160 for performing transmission inspection on a printed
substrate W held on the substrate table 60 will be described. The
X-ray irradiation unit 160 is supported by an X-ray source support
mechanism 150. First this X-ray source support mechanism 150 will
be described.
[0074] As illustrated in FIG. 11 and FIG. 12, the X-ray source
support mechanism 150 includes: a plate-shaped support plate 151
which is secured to the back surface of the beam 30; a pair of
elevating rails 152 and 153 which are fixed to the back surface of
the support plate 151 and extend in the Z axis direction; an
elevating slider 154 which is connected to the elevating rails 152
and 153; and a ball screw mechanism 155 which vertically drives the
elevating slider 154. The support plate 151 is a metal sheet member
that constitutes, along with the beam 30, a structure 20, and in
the illustrated example, the support plate 151 is firmly secured to
the beam 30. A stopper (not illustrated) is disposed in the support
plate 151, and the elevating slider 154 is guided so as to be
vertically movable in the Z axis direction within a stroke range
specified by this stopper. The stroke range is determined based on
the predetermined magnification required for the X-ray image of the
X-ray inspection device 10.
[0075] The magnification will be described with reference to FIG.
17A and FIG. 17B. In the following description, it is assumed that
the X-ray irradiation unit 160 is a dotted X-ray source shown in
FIG. 17A and FIG. 17B.
[0076] The distance L0, from the printed substrate W to the X-ray
camera unit 40, is always constant.
[0077] The elevating slider 154, on the other hand, directly
supports the X-ray irradiation unit 160. If the elevating slider
154 vertically moves along the elevating rails 152 and 153, the
X-ray source (X-ray irradiation unit) 160 integrally moves
vertically. If the X-ray source (X-ray irradiation unit) 160 moves
vertically, the distance L1, from the X-ray source (X-ray
irradiation unit) 160 to the printed substrate W held on the
substrate table 60, changes. In the same manner, if the X-ray
source (X-ray irradiation unit) 160 moves vertically, the distance
L2 (=L0+L1) of the reaching path of the X-rays, that are
transmitted from the X-ray irradiation unit 160 to the X-ray camera
unit 40 via the printed substrate W, also changes. The
magnification of the X-ray image captured by the X-ray camera unit
40 is L2/L1=1+(L0/L1). Therefore, if the X-ray source (X-ray
irradiation unit) 160 moves integrally, the distances L1 and L2
change, and as a result the magnification changes.
[0078] As illustrated in FIG. 10 and FIG. 17A, when the X-ray
irradiation unit 160 is in the lowered position, the reaching path
becomes the first distance L.sub.1st, and the magnification of the
X-ray image becomes a close up magnification, which is larger than
the original size. In other words, the X-ray irradiation unit 160
is in the close up position when lowered. As illustrated in FIG. 11
and FIG. 17B, when the X-ray irradiation unit 160 is in the
elevated position, the reaching path becomes the second distance
L.sub.2nd, which is longer than the first distance L.sub.1st. When
the X-ray irradiation unit 160 is elevated, the non-close up
magnification is a lower magnification in the wider angle than the
imaging in the close up position (greater magnification than the
original size). In other words, the X-ray irradiation unit 160 is
in the non-close up position when elevated. The elevating rails 152
and 153 guide the elevating slider 154 such that the X-ray
irradiation unit 160 moves vertically between the close up position
and the non-close up position.
[0079] On the other hand, the X-ray inspection device 10 of this
embodiment is constructed to execute the oblique view capturing,
where the X-rays RL are irradiated onto a printed substrate W at a
predetermined elevation angle .theta., and the essential inspection
area is imaged diagonally. In this oblique view capturing,
constraints are set in a later mentioned control unit 600 so that
the image is always captured at the close up position.
[0080] As illustrated in FIG. 11 and FIG. 12, the ball screw
mechanism 155 includes: a ball screw 155a which extends in the Z
axis direction and is rotatably supported on the back surface of
the support plate 151; a nut portion (not illustrated) which is
screwed into the ball screw 155a; a Z axis motor 155b which
rotary-drives the ball screw 155a around the Z axis; and a belt
mechanism 155c that transfers the output of the Z axis motor 155b
to the ball screw 155a. The ball screw 155a extends over
approximately the entire height of the support plate 151, so that
the X-ray irradiation unit 160 can vertically move in the stroke
range. The nut portion is fixed to the front surface of the
elevating slider 154, and receives the rotational force of the ball
screw 155a and transfers the force to move vertically to the
elevating slider 154. The Z axis motor 155b is installed on the
front surface of the support plate 151 in the Z axis direction with
the output axis thereof facing downward. The belt mechanism 155c
includes: an output pulley installed on the output axis of the Z
axis motor 155b; an input pulley installed at the lower end of the
ball screw 155a; and a belt wound around the pulleys, so that the
driving force of the Z axis motor 155b is transferred to the ball
screw 155a via the pulleys and the belt. In this way, the Z axis
ball screw mechanism 155 constitutes a magnification change unit
that changes the magnification of the X-ray image, by relatively
changing the positions of the X-ray irradiation unit 160 and the
X-ray camera 50 between the close up position (see FIG. 11) where
the direct distance for the X-rays irradiated from the X-ray
irradiation unit 160 to reach the X-ray camera 50 is short for
close up imaging, and the non-close up position (see FIG. 12) where
the direct distance for the X-rays irradiated from the X-ray
irradiation unit 160 to reach the X-ray camera 50 is longer than
the distance for the close up position.
[0081] In the illustrated example, the X-ray irradiation unit 160
has a housing 161, a high voltage generation unit (not illustrated)
which is housed inside the housing, and an X-ray irradiation source
that receives power from the high voltage generation unit and
irradiates X-rays.
[0082] As illustrated in FIG. 11 and FIG. 12, an R axis motor 170
is disposed on top of the X-ray irradiation unit 160. Since the
distribution of X-rays irradiated from the X-ray irradiation source
is not uniform, the distribution of irradiated X-rays is changed so
as to be located around the vertical axis by activating the R axis
motor 170, whereby the required essential inspection area is
imaged.
[0083] As illustrated in FIG. 1 and FIG. 13, a control unit 600 for
controlling the entire device is installed in the X-ray inspection
device 10. In this embodiment, a display panel 610 and a keyboard
620 are installed on the front surface of the X-ray inspection
device 10. A lamp 611 is erected on top of the X-ray inspection
device 10 in order to indicate the operation state. A power supply
device 630 is installed on the upstream side of the control unit
600 in the substrate conveying direction.
[0084] The control unit 600 has a main control unit (CPU) 601 which
is a microprocessor or the like, and a storage device 602, an X-ray
image board 603, a drive system board 605, a sensor system board
606, a display board 607, an input board 608, a communication board
609 and the like are connected to the main control unit 601.
[0085] The storage device 602 is ROM, RAM, an auxiliary storage
device or the like, and stores, for example, programs and master
data required for controlling each component of the X-ray
inspection device 10 and executing inspection, master data on an
inspection target product, such as a printed substrate W to be
inspected, surface mounted components and inspection items, and
master data defining inspection specifications on the inspection
target items.
[0086] The X-ray image board 603 is an interface for connecting the
X-ray camera 50 and the main control unit 601, and through this
X-ray image board 603, the main control unit 601 can execute the
transmission inspection of the inspection target product, based on
the X-ray images captured by the X-ray camera 50.
[0087] The drive system board 605 is an interface for connecting
various motors installed in the X-ray inspection device 10 (e.g.
respective X axis motors 44a, 141b, 114b, 144b, 155b, 185b of ball
screw mechanisms 44, 114, 141, 155 and 185) and an actuator, such
as an air cylinder 75, with the main control unit 601, and through
this drive system board 605, the main control unit 601 can control
the rotation direction, rotation amount, rotation speed, operation
timing or the like of various motors, and control the switching
operation of each air cylinder 71d, 72d and 75 of the conveyor unit
70.
[0088] The sensor system board 606 is an interface for connecting
various sensors of the X-ray inspection device 10 with the main
control unit 601, and through this sensor system board 606, the
main control unit 601 can detect the operation timing of each
component and whether or not the printed substrate W is present,
based on the detection result detected by these various
sensors.
[0089] The display board 607 is an interface for connecting the
display panel 610, which is installed on the front surface of the
X-ray inspection device 10, and the lamp 611 with the main control
unit 601, and through the display board 607, the main control unit
601 can display the control information on the display panel 610 as
the graphical user interface (GUI), or can flash the lamp 611
disposed on top of the X-ray inspection device 10 (see FIG. 1).
[0090] The input board 608 is an interface for connecting a
pointing device, such as the keyboard 620 installed on the front
surface of the X-ray inspection device 10, with the main control
unit 601, and through this input board 608, the main control unit
601 can accept data from the keyboard 620 or the like operated by
the user.
[0091] The communication board 609 is for executing data
communication with a host computer which manages a production
program of a facility where the X-ray inspection device 10 is
installed, and through this communication board 609, the main
control unit 601 is connected with the host computer via LAN and/or
WAN, and can acquire information on the inspection target items,
such as an item number of the target printed substrate W for
inspection.
[0092] Based on the programs and other data stored in the storage
device 602, the main control unit 601 controls each component of
the X-ray inspection device 10 according to the following
procedure.
[0093] As illustrated in FIG. 1 and FIG. 14, the main control unit
601 executes a substrate receiving operation (step S1). In the
substrate receiving operation, a printed substrate W, which
completed the upstream process, is conveyed by the substrate
conveyor 12, then the shutter mechanism of the board carry in/out
port 11d opens to open the board carry in/output port 11d, and the
printed substrate W is received. At this time, the substrate table
60 is driven by the X axis motor 114b of the X axis ball screw
mechanism 114, and moves toward the board carry on/output port 11d,
and receives the printed substrate W carried in by the substrate
conveyor 12. If this X-ray inspection device 10 is used in a
multi-item small lot production environment, the width dimensions
of the printed substrates W to be carried in vary, but according to
this carry in/receiving operation, the distance adjustment
mechanism 90 of the substrate table 60 is activated and adjusts the
space between the pair of conveyor frames 71 and 72 of the conveyor
unit 70 to a dimension matching with the width of the printed
substrate W to be carried in, based on the communication data
acquired from the host computer in advance. The printed substrate W
carried in through the board carry in/out port 11d is conveyed to
the substrate table 60 by the conveyor driving mechanism 80 of the
conveyor unit 70. After being carried in, the shutter mechanism on
the carry in side is activated and the board carry in/out port 11d
closes again, so that X-rays will not leak during X-ray
imaging.
[0094] The printed substrate W, which was carried in and moved to a
predetermined position, is clamped and held between the pair of
conveyor frames 71 and 72 of the conveyor unit 70 by the clamp
mechanism of the conveyor unit 70 (step S2).
[0095] When the printed substrate W is clamped, the substrate table
60 is driven by the X axis motor 114b of the X axis ball screw
mechanism 114 again, and moves to a predetermined position inside
the X-ray inspection device 10 (step S3). Thereby the printed
substrate W is set in the inspection position. Along with the
movement of the substrate table 60, the X axis motor 44a and the Y
axis motor 48a of the camera unit 40 are activated respectively for
X-ray imaging, so as to move the X-ray camera 50 to a predetermined
imaging position. In the X-ray irradiation unit 160, the R axis
motor 170 is driven in advance as required.
[0096] Then the main control unit 601 executes the X-ray imaging
inspection (step S5). In the X-ray imaging inspection, the main
control unit 601 executes the direct view inspection and the
oblique view inspection, which are combined according to the
inspection item of the essential inspection area of the printed
substrate W. In the oblique view inspection, the X-ray irradiation
unit 160 is moved to the close up position, and each of the ball
screw mechanisms 44 and 48 of the X-ray camera unit 40 is
activated, as illustrated in FIG. 10, whereby the X-ray camera 50
is moved to a position corresponding to the elevation angle of the
X-ray RL. In this state, the main control unit 601 activates the
X-ray camera 50 and captures an oblique view X-ray image, and
executes transmission inspection based on the captured image. The
inspection result is stored in an auxiliary storage of the storage
device 602.
[0097] Then the main control unit 601 determines whether imaging is
completed in all of the areas (step S7). If an un-imaged area
remains, the main control unit 601 returns to step S3, and repeats
the above mentioned processing. In this embodiment, in some cases
both X-ray imaging with a wide angle at a non-close up position and
close up X-ray imaging at a close up position must be executed for
a same essential inspection area, therefore in the determination in
step S7, the main control unit 601 returns to step S3 and repeats
the above mentioned processing, assuming that an un-imaged area
remains until all the required imaging inspections end for the same
area.
[0098] When imaging completes in all the areas, the main control
unit 601 executes processing to move the printed substrate W after
the inspection to the carry out position (step S8). In this carry
out movement operation, the X axis drive unit 110 of the table
driving mechanism 100 is activated again, and drives the substrate
table 60 to the downstream side in the substrate conveying
direction along the X axis direction (direction to approach the
board carry in/out port 11e in the illustrated example, see FIG.
2). When the substrate table 60 faces the board carry in/out port
11e on the carry out side, and the movement of the substrate table
60 stops, the clamp of the substrate table 60 is released (step S9)
and the carry out operation is executed (step S10). In the carry
out operation, the shutter mechanism on the carry out side is
activated and opens the board carry in/out port 11e. Then the
conveyor driving mechanism 80 activates the substrate conveyors 73
and 74 and carries out the inspected printed substrate W to the
substrate conveyor 14 on the carry out side. After carry out, the
shutter mechanism is activated. The shutter closes the board carry
in/out port 11e, to shift to the next operation. The X axis drive
unit 110 of the table driving mechanism 100 is activated again, and
drives the substrate table 60 to the upstream side in the substrate
conveying direction along the X axis direction (direction to
approach the board carry in/out port 11d in the illustrated
example, see FIG. 2).
[0099] After the carry out operation S10, the main control unit 601
determines whether inspection is completed for all the printed
substrates W (step S11). If there is an unprocessed printed
substrate W, the main control unit 601 returns to step S1, and
repeats the processing described above, and if the inspection
completes for all the printed substrates W, processing ends.
[0100] In the X-ray inspection processing described above,
particularly at a facility which performs multi-item small lot
production, printed substrates W having various width dimensions
are conveyed and receive X-ray inspection by the X-ray inspection
device 10. In this case, the substrate table 60 activates the
distance adjustment mechanism 90 and drives each conveyor frame 71
and 72 of the conveyor unit 70, corresponding to the width of the
target printed substrate W for inspection, but according to this
embodiment, the pair of conveyor frames 71 and 72 are disposed
symmetrically with respect to the opening 66 of the frame 61, and
the distance adjustment mechanism 90 equally drives the pair of
conveyor frames 71 and 72 to approach or depart from each other in
the Y axis direction, hence as illustrated in FIG. 16A and FIG.
16B, each of the conveyor frames 71 and 72 equally opens the
opening 66 in the width direction of the printed substrate W while
maintaining the symmetry with respect to the center line 120a along
the X axis direction (substrate conveying direction) of the opening
66. This means that the center line 120a, that bisects the width
direction of the printed substrate W, can be matched with the
center line 120a of the opening 66, and therefore when the oblique
view capturing is executed for a printed substrate W held on the
substrate table 60, an increase in the frame size (generation of
dimension dl shown in FIG. 16C and FIG. 16D), which occurs when the
substrate table 60P of Japanese Patent Application Laid-open No.
2003-315288 is used, can be prevented. Furthermore, a configuration
to symmetrically move the pair of conveyor frames 71 and 72 with
respect to the frame 61 is used, hence the opening 66 of the frame
61 can be opened extending over the entire width. When a printed
substrate W which requires only the direct view imaging is held,
even a printed substrate W whose width extends over the entire
width of the opening 66 can receive the X-ray RL inspection.
Further, the space is adjusted by equally moving the conveyor
frames 71 and 72, hence the driving time can be reduced (to 1/2 if
the driving speed is the same) compared with a case when one of the
conveyor frames 71 (72) is fixed and the other conveyor frame 72
(71) is movable. Moreover, the center line that bisects the width
direction of the printed substrate W can be matched with the center
line of the opening 66, which makes centering with the opening 66
for transmitting X-rays easier.
[0101] In this embodiment, as illustrated in FIG. 5, FIG. 8 and
FIG. 9, the frame 61 has four sides 62a, 63a, 64a and 65a that form
the opening 66 to a square in planar view, and at least two sides
62a and 63a in the X axis direction, out of the sides 62a, 63a, 64a
and 65a, have a bevel 62b (63b) which inclines such that the
downstream side in the X-ray irradiation direction of the X-ray
irradiation unit (lower side in this example) is wider. Therefore
according to this embodiment, the path of the X-rays RL can be
opened using the bevels 62b and 63b when the oblique view capturing
is performed, whereby the oblique view capturing becomes possible
for a wider printed substrate W.
[0102] In this embodiment, in particular, each of the pair of
conveyor frames 71 and 72 has a facing edge that the conveyor frame
faces in the Y axis direction, and a bevel 71i (72i), which
inclines such that the downstream side in the X-ray irradiation
direction of the X-ray irradiation unit is wider, is formed on the
facing edge. Therefore according to this embodiment, a wider
effective opening diameter for X-rays to transmit through the
opening 66 can be secured by the bevels 71i and 72i, whereby the
oblique view capturing becomes possible for an even wider printed
substrate W.
[0103] In this embodiment, as illustrated in FIG. 5 and FIG. 6, the
distance adjustment mechanism 90 includes: the double-end studs 91
and 92 which extend in the Y axis direction and of which screw
directions at one end and at the other end being set to be
opposite; the first nut mechanism 95 which is installed in one of
the conveyor frames 71 (72) and is screwed into one end of the
double-end stud 91 (92); the second nut mechanism 96 which is
installed in the other conveyor frame 72 (71) and is screwed into
the other end of the double-end stud 91 (92); the motor 94 for
driving each of the double-end studs 91 and 92; and the power
transfer unit 93 which transfers power of the motor 94 to the pair
of double-end studs 91 and 92 in a same direction at a same speed.
In this embodiment, if the motor 94 is activated, the torque is
transferred to each of the double-end studs 91 and 92 at the same
time in the same direction via the power transfer unit 93. If the
double-end studs 91 and 92 rotate in one direction (e.g.
clockwise), the nut mechanisms 95 and 96, which are screwed into
the double-end studs 91 and 92, transfer a force to the
corresponding conveyor frames 71 and 72 in directions for the
conveyor frames 71 and 72 to approach or depart from each other. If
the double-end studs 91 and 92 rotate in the other direction (e.g.
counterclockwise), the nut mechanisms 95 and 96, which are screwed
into the double-end studs 91 and 92, transfer a force to the
corresponding conveyor frames 71 and 72 in directions to move the
conveyor frames 71 and 72 in the opposite directions from above.
Therefore the pair of conveyor frames 71 and 72 can be
simultaneously driven using the single motor 94, whereby the drive
system can be simplified and the number of components can be
decreased.
[0104] In this embodiment, the substrate conveying mechanism
includes the pair of substrate conveyors 73 and 74 and the conveyor
driving mechanism 80 that drives the substrate conveyors 73 and 74,
and the conveyor driving mechanism 80 includes the motor 81, the
drive shaft 82 that is rotary-driven by the motor 81, and the first
output pulley 83 and the second output pulley 84 which form a pair
and are movably disposed in the axis direction of the drive shaft
82 in a state where rotation thereof around the axis of the drive
shaft 82 is restricted, the first output pulley 83 transferring the
power to one of the substrate conveyors 73 (74) and the second
output pulley 84 transferring the power to the other substrate
conveyor 74 (73). Therefore in this embodiment, the drive shaft 82
is rotated by the rotation of the motor 81. The torque thereof is
transferred to the substrate conveyors 73 and 74 via the first and
second output pulleys 83 and 84 respectively. Therefore, the
substrate conveyors 73 and 74 are simultaneously driven by the
single motor 81 in a same direction. The first and second output
pulleys 83 and 84 form a pair, so as to be movable in the axis
direction of the drive shaft, in a state where the rotation around
the axis of the drive shaft is restricted respectively. Hence the
power can be transferred to each of the substrate conveyors 73 and
74 without interrupting the displacement of the conveyor frames 71
and 72 by the distance adjustment mechanism 90.
[0105] The present invention is not limited to the embodiments
described above, but numerous modifications can be made without
departing from the true spirit and scope of the invention.
[0106] For example, when an oblique view image is captured, the
X-ray camera 50 can image at a position relatively displaced from
the non-close up position toward the close up position, and need
not be relatively displaced to the close up position with
exactness.
[0107] In this embodiment, the X-ray camera 50 is disposed below
the substrate table 60 and the X-ray irradiation unit 160 is
disposed above the substrate table 60, but the X-ray camera 50 may
be disposed above the substrate table 60 and the X-ray irradiation
unit 160 below the substrate table 60.
[0108] In this embodiment, the X-ray irradiation unit 160 is
vertically moved by the X-ray source support mechanism 150, but the
X-ray irradiation unit 160 may be fixed to a predetermined position
and the X-ray camera 50 may be driven in the Z axis direction.
[0109] The bevels at the edges which mark out the opening of the
frame may be formed in the Y axis pieces 64 and 65, instead of the
X axis pieces 62 and 63 as described above.
[0110] A configuration where the X-ray irradiation unit is disposed
below the substrate table and the X-ray camera is disposed above
the substrate table may be used.
[0111] When the oblique view capturing is performed, a
configuration of fixing the X-ray camera and moving the X-ray
irradiation unit may be used. Alternatively, a configuration of
moving both the X-ray camera and the X-ray irradiation unit may be
used.
[0112] Moreover, an optical camera may be used as well, so that the
appearance inspection and the X-ray inspection are executed
simultaneously.
[0113] Needless to say, various other modifications can be made
within the scope of the claims of the present invention.
INDUSTRIAL APPLICABILITY
[0114] The present invention can be applied to an inspection
technology field for inspecting essential inspection areas of
precision components using X-rays.
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